JP4807012B2 - Biodegradable nonwoven fabric with excellent hydrolysis resistance - Google Patents

Description

The present invention relates to an aliphatic polyester-based biodegradable nonwoven fabric excellent in hydrolysis resistance, and has a favorable production environment without generation of irritating odors when producing the nonwoven fabric, including civil engineering materials. The present invention relates to a biodegradable spunbonded nonwoven fabric that can be suitably used for each application.

In recent years, non-woven fabrics made of various biodegradable resins have been proposed due to increasing environmental awareness.
Biodegradable nonwoven fabric is chemically decomposed by the action of sunlight, ultraviolet rays, heat, water, enzymes, microorganisms, etc. in natural environments, and further disintegrates morphologically. It can be disposed of by leaving it outdoors. Even if incineration is performed, the biodegradable resin generally has a lower heat of combustion than polyester, polypropylene, nylon, and other resins used in conventional nonwoven fabrics, so it does not damage the incinerator during incineration. There is a merit.

  In addition, among biodegradable resins, plant resources that take in carbon dioxide from the atmosphere and grow can be used as raw materials, and it can be expected that global warming can be suppressed by the circulation of carbon dioxide, and the problem of resource depletion can be solved. Because of this possibility, attention has been focused on resins starting from plant resources, that is, resins using biomass.

  However, conventional biodegradable resins using biomass have not been used as general-purpose plastics because they have problems such as low mechanical properties and heat resistance and high production costs.

On the other hand, in recent years, a polylactic acid resin using lactic acid obtained by starch fermentation as a raw material has attracted attention as a biodegradable resin having relatively high mechanical properties and heat resistance and low production costs.
Development of polylactic acid non-woven fabric using polylactic acid resin is preceded by civil engineering and agricultural materials that make use of biodegradability, but as a subsequent use, it is applied to life materials, industrial materials, and vehicle materials. Is also expected.

  However, polylactic acid fibers and non-woven fabrics comprising the same have a problem that the product life is short in applications where high strength retention is required because hydrolysis proceeds in the use environment.

  In order to improve this problem, the mechanical properties of the non-woven fabric are improved by using a polylactic acid-based sheath fiber made of a polylactic acid-based sheath-core composite fiber and having a melting point of 20 ° C. or more lower than that of the core component polylactic acid-based resin. In addition, a biodegradable coating material for agricultural use made of a polylactic acid-based long-fiber non-woven fabric is known in which the strength retention after irradiation for 300 hours is 50% or more in a weather resistance test using a weather meter (Patent Document 1) reference).

  However, since the biodegradable coating material for agriculture does not take any measures against hydrolysis, which is a major factor in the process of reducing the strength of polylactic acid fiber, hydrolysis reaction occurs under the influence of rain dew during use. Further, there has been a drawback that the strength of the fiber, and thus the nonwoven fabric, is reduced.

On the other hand, a biodegradable plastic composition having a hydrolysis resistance improved by adding a polycarbodiimide compound is known (see Patent Document 2).
However, the polycarbodiimide compound described in Patent Document 2 has low dispersibility in polylactic acid, is easy to cause gelation, is insufficient in improving hydrolysis resistance, and is applied to fibers and nonwoven fabrics. When the polymer added with the polycarbodiimide compound is melt-spun, it becomes difficult to apply to the production of industrial fibers and non-woven fabrics. There was a problem that the working environment deteriorated due to the generation of the irritating decomposition gas.

  In addition, by adding a monocarbodiimide compound, polylactic acid fiber with improved hydrolysis resistance, or a specific polysiloxane having two or more carbodiimide groups in the molecule and whose ends are sealed with carboxylic acid A polylactic acid fiber obtained by mixing a carbodiimide compound has been proposed (Patent Document 3 and Patent Document 4).

These polylactic acid fibers are said to be suitable for various fiber products because there is little generation of irritating decomposition gas at the time of production, but when producing biodegradable nonwoven fabrics using these polylactic acid fibers, Non-woven fabrics are not only damaged by thermal bonding and fiber entanglement due to needle punching during their production, so even if the fibers constituting the non-woven fabric have excellent hydrolysis resistance, it remains It did not lead to improvement in hydrolysis resistance of the nonwoven fabric or improvement in strength retention under wet heat conditions.
JP 2000-333542 A Japanese Patent Laid-Open No. 11-80522 JP 2001-261797 A JP 2004-332166 A

  The present invention provides an aliphatic polyester-based biodegradable nonwoven fabric excellent in hydrolysis resistance, and has a good production environment without generation of irritating odors when producing the nonwoven fabric. It aims at providing the biodegradable nonwoven fabric which can be used suitably for various uses including materials.

In order to solve this problem, the biodegradable nonwoven fabric of the present invention has the following configuration (1) or (2).
(1) A biodegradable non-woven fabric containing fibers made from an aliphatic polyester resin having a carboxyl group at the molecular chain terminal, and a monocarbodiimide compound having a 5% weight loss temperature of 170 ° C. or higher. The terminal carboxyl group is partially or completely blocked, and the rate of decrease in the strength elongation index under a wet heat atmosphere is less than 30% , and the aliphatic bisamide and / or the alkyl-substituted aliphatic monoamide is reduced to 0. A biodegradable spunbonded nonwoven fabric containing 1 to 5.0 wt% .
(2) A biodegradable nonwoven fabric containing a core-sheath composite fiber made of an aliphatic polyester resin having a carboxyl group at the molecular chain end, and only the sheath component resin of the core-sheath composite fiber has a 5% weight loss temperature of 170. A part or all of the terminal carboxyl group is blocked by a monocarbodiimide compound at a temperature of not lower than ° C. , and the sheath component ratio of the core-sheath composite fiber is 5 to 70 vol%, and the rate of decrease in the strength elongation index under a moist heat atmosphere Is a biodegradable spunbond nonwoven fabric characterized by containing 0.1 to 5.0 wt% of an aliphatic bisamide and / or an alkyl-substituted aliphatic monoamide .

Furthermore, in the biodegradable nonwoven fabric of the present invention of (1) or (2), more preferably, it has the following configuration (3) or (4) .
(3) The biodegradable spunbonded nonwoven fabric according to (1) or (2) above , wherein the terminal carboxyl group concentration is 0 to 20 equivalent / ton .
(4) The biodegradable spunbonded nonwoven fabric according to any one of (1) to (3) above , wherein the aliphatic polyester resin is a polylactic acid resin

Furthermore, the biodegradable spunbonded nonwoven fabric of the present invention described above is used for the usage shown in the following (5) and exhibits a unique effect.
(5) A material comprising the biodegradable spunbonded nonwoven fabric according to any one of (1) to (4) above .

According to the present invention, a biodegradable spunbonded nonwoven fabric having good production environment without producing irritating odor or the like during production and excellent in hydrolysis resistance can be obtained.
The biodegradable spunbond nonwoven fabric of the present invention can be suitably used for various uses including civil engineering materials.

Biodegradable spunbond nonwoven fabric of the present invention is a biodegradable nonwoven fabric comprising the fiber of the aliphatic polyester resin having a carboxyl group at a molecular chain end as a raw material, the carboxyl group of the molecular chain terminals, 5% by weight It is a biodegradable spunbonded nonwoven fabric using fibers made of an aliphatic polyester resin that is partially or entirely end-capped with a monocarbodiimide compound having a decreasing temperature of 170 ° C. or higher .

The biodegradable nonwoven fabric of the present invention is preferably a long-fiber nonwoven fabric manufactured by the spunbond method because it is suitable for various applications.

  In the case of long-fiber non-woven fabric, for example, after extruding the molten polymer from the nozzle and drawing it with a high-speed suction gas, the fibers are collected on a moving conveyor to form a web, which is further continuously bonded and entangled. Etc. can be manufactured by a so-called spunbond method or the like which is formed into a sheet integrally.

Forming method of the nonwoven fabric, it is important to strength and elongation index decreasing rate under wet heat atmosphere to form the biodegradable nonwoven fabric is less than 30%, in the case of spunbonded nonwoven fabric, the fibers constituting more highly order to orient the crystallization, spinning speed preferably 2000 m / min or more, more preferably 3000 m / min or more, more preferably set to 4000 m / min or more, and the crimp area ratio when heat bonding the web is excessively large heat-bonded Since the strength reduction proceeds from the portion that has been made, the area ratio of the pressure bonding when thermally bonding is preferably 5 to 30%, more preferably 10 to 25%. A biodegradable nonwoven fabric having a reduction rate of less than 30% can be produced .

The lower limit of the rate of decrease in the strength elongation index of the biodegradable spunbonded nonwoven fabric according to the present invention is up to about 1%, more preferably up to 2%.

In the biodegradable spunbond nonwoven fabric of the present invention, the aliphatic polyester resin used as a raw material for the fibers constituting the biodegradable nonwoven fabric is not particularly limited, but is a polylactic acid resin, a polybutylene succinate resin, Polycaprolactone resin, polyethylene succinate resin, polyglycolic acid resin, polyhydroxybutyrate resin, etc. are preferably used. Among them, polylactic acid resin is particularly preferable because of its relatively high mechanical properties and heat resistance and low production cost. Used. A plurality of these resins may be used in combination. As a method for compounding the resin, a method in which a plurality of types of melted resins are mixed, and a method in which two types of resins are formed into a composite fiber form such as a core-sheath type, a side-by-side type, a sea-island type, or a multileaf type is preferable It is.

In the biodegradable spunbond nonwoven fabric of the present invention, a crystal nucleating agent, a matting agent, a pigment, an antifungal agent, an antibacterial agent, a flame retardant, a lubricant, and the like are added to the biodegradable resin as long as the effects of the present invention are not impaired. In particular, in order to further reduce the generation of irritating odor when producing a biodegradable spunbond nonwoven fabric, an aliphatic bisamide and / or an alkyl-substituted aliphatic monoamide may be added. It is important to add in the range of 0.1 to 5.0 wt%, more preferably in the range of 0.3 to 4.0 wt%, and in the range of 0.5 to 2.0 wt% More preferably. An aliphatic bisamide or an alkyl-substituted aliphatic monoamide may be used alone, or a combination of both may be used. When the content of the aliphatic bisamide and / or the alkyl-substituted aliphatic monoamide is less than 0.1 wt%, the release effect of the aliphatic bisamide and / or the alkyl-substituted aliphatic monoamide is sufficiently exerted. In the case of a spunbond nonwoven fabric production method having a thermal bonding step, the aliphatic polyester resin containing the carboxyl group terminal of the aliphatic polyester resin and the unreacted carbodiimide compound is likely to adhere to a heat roll or the like. Since the compound is thermally decomposed and an unpleasant pungent odor is likely to occur, it is not preferable. On the other hand, if the content exceeds 5.0 wt%, the spinnability is not stable and spinning may not be possible, which is not preferable.

The aliphatic bisamide used in the biodegradable spunbond nonwoven fabric of the present invention is not particularly limited, but is preferably a saturated fatty acid bisamide, an unsaturated fatty acid bisamide, an aromatic fatty acid bisamide, and the like, for example, methylene bisstearic acid Examples thereof include amide, ethylene bis-stearic acid amide, ethylene bis-valmitic acid amide, ethylene bis-oleic acid amide, and a plurality of these may be used in combination.

The alkyl-substituted aliphatic monoamide used in the biodegradable spunbond nonwoven fabric of the present invention is not particularly limited, but has a structure in which an amide hydrogen such as a saturated fatty acid monoamide or an unsaturated fatty acid monoamide is substituted with an alkyl group. The compound is preferably N-lauryl lauric acid amide, N-palmityl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, and the like. Also good.

  The method of adding the aliphatic bisamide and / or the alkyl-substituted aliphatic monoamide to the resin used as a raw material for spinning is not particularly limited, but the raw material resin and the substance to be added are previously heated and melt mixed. A method of preparing a master chip and adding the necessary amount to the raw material resin during spinning to adjust the amount of the added substance is preferable.

  As the polylactic acid resin, poly (D-lactic acid), poly (L-lactic acid), a copolymer of D-lactic acid and L-lactic acid, or a blend thereof is preferable.

In the biodegradable spunbonded nonwoven fabric of the present invention, a hydrolysis resistant stabilizer is used to obtain a biodegradable nonwoven fabric having a good production environment without generation of irritating odors and the like and excellent in hydrolysis resistance. As described above, it is important that a carbodiimide compound is added, and a part or all of the terminal carboxyl groups of the aliphatic polyester resin which is a raw material of the fiber constituting the biodegradable nonwoven fabric is blocked with the compound.

The carbodiimide compound used as a hydrolysis-resistant stabilizer in the biodegradable spunbonded nonwoven fabric of the present invention is only required to be suitable for the use of the resulting biodegradable nonwoven fabric. When a monocarbodiimide compound is used, 5% by weight It is important that the decrease temperature (hereinafter referred to as “T5%”) is a monocarbodiimide compound having a temperature of 170 ° C. or higher , and more preferable is a monocarbodiimide compound having a T5% of 190 ° C. or higher.

  In monocarbodiimide compounds having a T5% of less than 170 ° C., the hydrolysis resistance stabilizer added during resin molding is decomposed and / or vaporized, resulting in a decrease in heat resistance and quality of the nonwoven fabric. There are problems such as that the polyester does not react and act effectively at the carboxyl group terminals, and a sufficient effect of improving hydrolysis resistance cannot be obtained, and yarn breakage frequently occurs during spinning during the production of a nonwoven fabric. Here, the 5% weight loss temperature is a sample weight of about 10 mg measured by a MACTGCIENCE “TG-DTA2000S” TG-DTA measuring device in a nitrogen atmosphere at a rate of temperature increase of 10 ° C./min. This is the temperature obtained as the temperature when the weight is reduced by 5% with respect to the sample weight before the start of measurement.

  Examples of monocarbodiimide compounds that can be used as a hydrolysis-resistant stabilizer in the biodegradable nonwoven fabric of the present invention include, for example, N, N′-di-2,6-diisopropylphenylcarbodiimide, N, N′-di -2,6-di-tert. -Butylphenylcarbodiimide, N, N'-di-2,6-diethylphenylcarbodiimide, N, N'-di-2-ethyl-6-isopropylphenylcarbodiimide, N, N'-di-2-isobutyl-6 Isopropylphenylcarbodiimide, N, N′-di-2,4,6-trimethylphenylcarbodiimide, N, N′-di-2,4,6-triisopropylphenylcarbodiimide, N, N′-di-2,4 Examples thereof include 6-triisobutylphenyl carbodiimide. The monocarbodiimide compound used as a hydrolysis-resistant stabilizer may be a single type or a mixture of a plurality of types, but N is preferred in terms of heat resistance and reactivity and affinity with aliphatic polyesters. , N′-di-2,6-diisopropylphenylcarbodiimide (hereinafter referred to as TIC) is preferable, and when a plurality of types of monocarbodiimide compounds are used in combination, 50% or more of the total amount of monocarbodiimide compounds used as end-capping agents Is preferably TIC.

  As a method of blocking the terminal carboxyl group with the monocarbodiimide compound, it can be obtained by reacting an appropriate amount of the monocarbodiimide compound as a terminal blocking agent in the molten state of the aliphatic polyester. From the viewpoint of suppressing low molecular weight substances, it is preferable to add and react the monocarbodiimide compound after completion of the polymerization reaction of the polymer.

  Examples of the mixing and reaction of the above-described monocarbodiimide compound and aliphatic polyester include, for example, a method of adding a monocarbodiimide compound to a molten aliphatic polyester immediately after the completion of the polycondensation reaction, stirring and reacting, and an aliphatic polyester chip. A method of adding and mixing a monocarbodiimide compound and then kneading and reacting in a reaction vessel or an extruder (hereinafter referred to as melt kneading). A liquid monocarbodiimide compound is continuously added to an aliphatic polyester with an extruder and kneaded and reacted. For example, a blend chip obtained by mixing a master chip of an aliphatic polyester containing a high concentration of a monocarbodiimide compound and a homochip of an aliphatic polyester is kneaded and reacted with an extruder or the like.

In addition, although it becomes things other than the biodegradable spunbond nonwoven fabric of this invention , when a polycarbodiimide compound is used as a carbodiimide compound as a hydrolysis-resistant stabilizer, formula (a)

で表される４，４’−ジシクロヘキシルメタンジイソシアネート、および式（ｂ）

And 4,4′-dicyclohexylmethane diisocyanate represented by formula (b)

で表されるイソホロンジイソシアネート、および、式（ｃ）

And an isophorone diisocyanate represented by the formula (c)

で表されるテトラメチルキシリレンジイソシアネートの少なくとも１種に由来し、分子中に２以上のカルボジイミド基を有し、かつそのイソシアネート末端がカルボン酸で封止されてなるポリカルボジイミド化合物であることが好ましい。

It is preferably a polycarbodiimide compound derived from at least one tetramethylxylylene diisocyanate represented by the formula, having two or more carbodiimide groups in the molecule, and having the isocyanate terminal sealed with a carboxylic acid. .

  The polycarbodiimide compound is a 4,4′-dicyclohexylmethane diisocyanate (hereinafter abbreviated as HMDI) represented by the above formula (a) or an isophorone diisocyanate (hereinafter abbreviated as IPDI) represented by the above formula (b). ), Or carbodiimide derived from any one of tetramethylxylylene diisocyanate (hereinafter abbreviated as TMXDI) represented by the above formula (c), or a mixture of the above compounds, or a mixture of the three The main component is a carbodiimide derived from any mixture and having 2 or more carbodiimide groups, preferably 5 or more carbodiimide groups in the molecule. The upper limit of carbodiimide groups in polycarbodiimide is 20.

  Such a carbodiimide can be produced by a carbodiimidization reaction accompanied by a decarbonation reaction using HMDI, IPDI, TMXDI or a mixture of the above compounds or a mixture of the above compounds as a raw material. Of these, carbodiimide using 50% by weight or more of HMDI is preferable and carbodiimide using 80% by weight or more of HMDI is more preferable because the obtained fiber has excellent mechanical properties.

Further, as a polycarbodiimide compound to be added to the biodegradable spunbond nonwoven fabric, even in the presence of polycarbodiimide compound unreacted aliphatic polyester resin, the thermal stability spinnability deteriorated during nonwoven production to excellent And generation of an irritating gas can be suppressed, and it is necessary that the end of the isocyanate is sealed with a carboxylic acid. The carboxylic acid preferably used is a monocarboxylic acid, for example, cyclohexanecarboxylic acid, benzoic acid, trimellitic anhydride, 2-naphthoic acid, nicotinic acid, isonicotinic acid, 2-furic acid, propionic acid, butyric acid, isochoric acid. Examples include butyric acid, methacrylic acid, palmitic acid, stearic acid, oleic acid, cinnamic acid, glyceric acid, acetoacetic acid, benzylic acid, and anthranilic acid. Among these, cyclohexanecarboxylic acid is most preferred.

  In order to reduce the amount of pyrolysis gas generated by thermal degradation of the unreacted polycarbodiimide compound, the amount of polycarbodiimide compound added is equal to or less than twice the total carboxyl group terminal amount of the aliphatic polyester as the carbodiimide group equivalent. It is preferable to do. The addition amount of the polycarbodiimide compound is more preferably 1.5 times equivalent or less, more preferably 1.2 times equivalent or less of the total carboxyl group terminal amount.

In order to obtain a biodegradable spunbond nonwoven fabric excellent in hydrolysis resistance in the biodegradable spunbond nonwoven fabric of the present invention, an aliphatic polyester resin used as a raw material for fibers constituting the biodegradable spunbond nonwoven fabric with a carbodiimide compound It is important that some or all of the terminal carboxyl groups are blocked, and the fiber form is not particularly limited. The fineness can also be used in the range usually used for spunbonded nonwoven fabrics.

However, it is preferable that the hydrolysis resistance can be adjusted according to the application to be used. However, the adjustment of the hydrolysis resistance can be controlled not only by adjusting the content of the monocarbodiimide compound but also by the fiber form. For example, a biodegradable spunbond nonwoven fabric is composed of a core-sheath type composite fiber, and only the sheath component resin of the core-sheath type composite fiber contains a monocarbodiimide compound, and a part or all of the terminal carboxyl groups of the compound are partially If the aliphatic polyester resin is sealed, there is an advantage that the hydrolysis resistance of the biodegradable spunbond nonwoven fabric can be adjusted by adjusting the sheath component ratio. The core-sheath type composite fiber may be a so-called sea-island type composite fiber having many core components, or may be a biodegradable resin in which the core component resin and the sheath component resin are different.

In the biodegradable spunbond nonwoven fabric of the present invention, when the core-sheath type composite fiber is applied to adjust the hydrolysis resistance of the biodegradable spunbond nonwoven fabric, the ratio of the sheath component is the total of the core-sheath type composite fiber. It is important that the cross-sectional area is 5 to 70 vol%, and more preferably 10 to 60 vol%. When the sheath component ratio is less than 5 vol%, the core component resin to which the hydrolysis-resistant stabilizer is not added is easily exposed on the fiber surface during the production or use of the biodegradable spunbond nonwoven fabric. Since the progress of the decomposition is promoted and the hydrolyzability of the biodegradable spunbond nonwoven fabric cannot be adjusted, it is not preferable.

On the other hand, when the sheath component ratio exceeds 70 vol%, it is not preferable because the hydrolyzability of the biodegradable spunbonded nonwoven fabric becomes substantially impossible to adjust. The core-sheath-type conjugate fiber used in the present invention can be produced using a known core-sheath-type conjugate fiber production apparatus, and the resin serving as the core component and the resin serving as the sheath component are separated into separate polymer introduction tubes. The composite spinneret can be obtained by using a composite spinneret that can be filtered (aggregated) in a split flow state after being filtered in each filtration chamber.

It is preferable that the terminal carboxyl group density | concentration of the aliphatic polyester resin used as the raw material of the fiber which comprises the biodegradable spunbond nonwoven fabric of this invention is 0-20 equivalent / ton, and it is 0-15 equivalent / ton. More preferably, it is more preferably 0 to 10 equivalent / ton. If the terminal carboxyl group concentration exceeds 20 equivalents / ton, the desired hydrolysis resistance cannot be obtained, which is not preferable. In addition, the terminal carboxyl concentration as used in the field of this invention means the value measured with the measuring method mentioned later.

In the biodegradable spunbond nonwoven fabric of the present invention, for the characteristic values such as fabric weight, thickness, high elongation, air flow rate, etc., civil engineering materials, agricultural materials, living materials, industrial materials, vehicle materials, building materials, etc. The characteristic value is not particularly limited as long as it is a characteristic value suitable for each application, but the strength elongation index decrease rate under a wet heat atmosphere that is an index of hydrolysis resistance of the nonwoven fabric is less than 30%. It is necessary, and it is preferably less than 20%, more preferably less than 10%. In addition, the strong elongation index reduction rate in a wet heat atmosphere as referred to in the present invention refers to the strong elongation index reduction rate described in the column (5) of Examples described later.

  The material in the present invention refers to each material of civil engineering materials, agricultural materials, living materials, industrial materials, vehicle materials, and building materials.

  The civil engineering material in the present invention is not particularly limited as long as it is a material used for civil engineering, for example, a herbicidal sheet, a tree planting pot, a root winding material, a bank reinforcement, a slope protection material, These include revetment sheets, soft ground surface treatment materials, suction prevention materials, and tunnel drainage materials.

  The agricultural material in the present invention is not particularly limited as long as it is a material used for agriculture and horticulture, for example, a beak sheet, a seedling pot, a seedling sheet, a root prevention sheet, a sugar content-up sheet, These include multi-sheets, insect-proof sheets, insect-proof bags, agricultural tape materials, seed vat sheets and seed vat tapes.

  The living material in the present invention is not particularly limited as long as it is a material used for daily items. For example, handbags, souvenir bags, wrapping materials, suit covers, cleaning covers, simple clothing, masks, wipers Pillow covers, futon storage bags, electrical product packaging materials, food packaging materials, tea bags, draining bags, etc.

  The industrial material in the present invention is not particularly limited as long as it is a material used for industrial use. For example, it is a filter, an electric wire holding material, an industrial wiper, an abrasive cloth, a battery separator, and the like. is there.

  The vehicle material in the present invention is not particularly limited as long as it is a material used for various vehicles such as automobiles, trains, airplanes, and ships. For example, a ceiling material, a floor mat, a sheet material, a different material is used. Sound prevention materials, spare tire cover materials, trunk room interior materials, airbag wrapping materials, etc.

  The building material in the present invention is not particularly limited as long as it is a material used for construction, for example, a moisture-permeable waterproof sheet, a roofing roof material, a roofing material, a waterproof coating material, a sound insulating material, It is a soundproofing material, a sound absorbing material, a heat insulating material, a decorative board backing material, and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited by these Examples. In addition, each characteristic value in the following Example is measured by the following method.

(1) Mw (weight average molecular weight)
Tetrahydrofuran was mixed with the chloroform solution of the sample to prepare a measurement solution, which was measured at 25 ° C. using a gel permeation chromatograph (GPC) Waters 2690 manufactured by Waters, and Mw was determined in terms of polystyrene. The measurement was performed at three points for each sample, and the average value was defined as each Mw.

(2) Melting point (° C)
Using a differential scanning calorimeter DSC-2 manufactured by Perkin Elma Co., Ltd., measuring at a temperature rising rate of 20 ° C./min, reading the temperature that gives the extreme value in the melting endothermic curve to the first decimal place, The value rounded to the first decimal place was taken as the melting point.

(3) Single fiber fineness (dtex)
Ten small piece samples are taken at random from the nonwoven fabric, photographed at 500 to 3000 times with a scanning electron microscope, 10 from each sample, 100 fiber diameters are measured, and the fiber diameter is calculated from the average value. The fineness was calculated by correcting this with the density of the polymer. The second decimal place of the calculated value was rounded off.

(4) Weight per unit (g / m ² )
Based on JIS L 1906 (2000 edition) 5.2, three samples of 30 cm in the vertical direction and 30 cm in the horizontal direction were taken, the weight of each sample was measured, and the average value of the obtained values per unit area The weight per unit area <A> of the nonwoven fabric was calculated by rounding off the first decimal place of the obtained value.

(5) Strong elongation index decrease rate (%)
Each sample of width direction 5 cm × length direction 30 cm (longitudinal direction) and length direction 5 cm × width direction 30 cm (lateral direction) of the nonwoven fabric was placed in a constant temperature bath at a temperature of 60 ± 5 ° C. and a relative humidity of 80 ± 5%. It was left in the state suspended for days.

  Based on JIS L 1906 (2000 edition) 5.3.1, samples left in the above-mentioned temperature-controlled bath and samples before being left in the temperature-controlled bath (collected simultaneously when collecting samples left in the temperature-controlled bath) ) Under the conditions of a grip interval of 20 cm and a tensile speed of 10 cm / min, the tensile test was carried out at 5 points in each of the machine direction and the transverse direction, and the maximum strength (N / 5 cm unit, decimal point) Second rounded) and elongation at break (% units, rounded to the second decimal place).

The sample was left in a constant temperature bath, a maximum strength of the average value of the longitudinal five points to T _MD14, the maximum strength of the average value of the lateral direction of 5 T _CD14, an average elongation at break in the longitudinal direction 5 points E _MD14 , the average value of elongation at break in 5 points in the horizontal direction is E _CD14, and for samples before standing in the thermostatic chamber, the average value of 5 points in the vertical direction is T _MD0 , and the maximum strength in 5 points in the horizontal direction. the average value T _CD0, the average of breaking elongation in the longitudinal direction 5 points E _MD0, the average value of the elongation at break in the transverse direction 5 points was E _CD0.

The average value for each of the five points was rounded off to the second decimal place.
And using these measured values, the strength elongation index reduction rate was calculated by the following formula. Also in this case, the value rounded to the second decimal place was adopted.
Strength and elongation index decrease rate (%) = 100-100 × {( T MD14 × √E MD14) + (T CD14 × √E CD14)} / {(T MD0 × √E MD0) + (T CD0 × √E _CD0 )}

  Each sample used for the measurement had a size of 5 cm × 30 cm, and the basis weight was measured in advance before being put into each tank. The difference from the basis weight of the same sample measured in the above (3) was within ± 2%. Only the thing was used for the measurement of the strength elongation index retention (decrease rate).

(6) Carboxyl group terminal concentration (equivalent / ton)
The precisely weighed sample was dissolved in o-cresol (5% moisture), and an appropriate amount of dichloromethane was added to this solution, followed by titration with a 0.02 N KOH methanol solution. At this time, an oligomer such as lactide, which is a cyclic dimer of lactic acid, is hydrolyzed to generate a carboxyl group terminal, so that all of the carboxyl group terminal of the polymer, the carboxyl group terminal derived from the monomer, and the carboxyl group terminal derived from the oligomer are combined. The carboxyl group terminal concentration obtained is obtained.

Comparative Example 1
TIC was added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt-kneading to produce a chip having a TIC content of 5.0 wt%. The prepared TIC 5.0 wt% chip and a polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. are mixed so that the mixing ratio of the TIC 5.0 wt% chip is 20 wt%. It was mixed with an apparatus to obtain a raw material for the spunbonded nonwoven fabric. This raw material does not contain aliphatic bisamide or the like and is a comparative example.

The obtained raw material was melted at 230 ° C., spun from the pores at a die temperature of 235 ° C., spun at a spinning speed of 4300 m / min by an ejector, and the web obtained by collecting on the moving net conveyor was A spunbonded non-woven fabric with a single fiber fineness of 1.6 dtex and a basis weight of 30 g / m ² was produced by thermocompression bonding with an embossing roll and a flat roll having a convex area of 16% under conditions of a temperature of 145 ° C. and a linear pressure of 25 kg / cm ² . . The resulting spunbonded nonwoven fabric had a terminal carboxyl group concentration of 6.5 equivalents / ton and a strong elongation index reduction rate of 18.5%.

Since this biodegradable nonwoven fabric is a spunbond nonwoven fabric with a strong elongation index decrease rate of 18.5% and a basis weight of 30 g / m ² , agricultural materials such as sticky sheets and insect-proof bags, and packaging of electrical products It could be judged to be optimal for uses such as household materials such as wood and cleaning covers, industrial materials such as filters, automotive materials such as ceiling materials, building materials such as roof coverings and decorative backing materials.

Comparative Example 2
2 kg of HMDI, 180 g of cyclohexanecarboxylic acid as end-capping agent, 10 g of 3-methyl-1-phenyl-2-phospholene-1-oxide as a carbodiimidization catalyst, and bubbling nitrogen for 12 hours at 190 ° C. By reacting, a polycarbodiimide compound having a polymerization degree of 8 (hereinafter referred to as polycarbodiimide compound A) was obtained.

A polycarbodiimide compound A was added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt kneading to produce a chip having a polycarbodiimide compound A content of 5.0 wt%. The prepared polycarbodiimide compound A 5.0 wt% chip, a polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C., and the mixing ratio of the polycarbodiimide compound A 5.0 wt% chip is 10 wt%. The mixture was mixed with a chip mixer so that the raw material of the spunbond nonwoven fabric was obtained. The obtained raw material was melted at 230 ° C., spun from the pores at a base temperature of 235 ° C., spun at a spinning speed of 4100 m / min by an ejector, and the web obtained by collecting on the moving net conveyor was collected. A spunbonded non-woven fabric with a single fiber fineness of 1.2 dtex and a basis weight of 50 g / m ² is manufactured by thermocompression bonding with an embossing roll and flat roll with a convex area of 16% at a temperature of 145 ° C. and a linear pressure of 25 kg / cm. did. The terminal carboxyl group concentration of the obtained spunbonded nonwoven fabric was 7.6 equivalent / ton, and the strong elongation index reduction rate was 16.2%. This spunbonded nonwoven fabric uses a polycarbodiimide compound as a hydrolysis-resistant stabilizer and does not contain aliphatic bisamide or the like, and is a comparative example.

Since this biodegradable nonwoven fabric is a spunbonded nonwoven fabric with a strength elongation reduction rate of 16.2% and a basis weight of 50 g / m ² , it can be used for agricultural materials such as nursery pots, sugar up sheets, and packaging of electrical products. Applications such as bags, wrapping materials, household materials such as simple clothing, industrial materials such as filters, automotive materials such as ceiling materials, airbag wrapping materials, trunk room interior materials, building materials such as roofing materials, roofing materials, and sound insulation materials It was possible to judge that it was optimal.

Comparative Example 3
2 kg of HMDI, 180 g of benzoic acid as end-capping agent, 10 g of 3-methyl-1-phenyl-2-phospholene-1-oxide as a carbodiimidization catalyst and reaction at 190 ° C. for 12 hours while bubbling nitrogen Thus, a polycarbodiimide compound having a degree of polymerization of 8 (hereinafter referred to as polycarbodiimide compound B) was obtained. Similar to Comparative Example 2, this spunbonded nonwoven fabric uses a polycarbodiimide compound as a hydrolysis-resistant stabilizer and does not contain aliphatic bisamide or the like, and is a comparative example.

A polycarbodiimide compound B was added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt kneading to produce a chip having a polycarbodiimide compound A content of 5.0 wt%. The prepared polycarbodiimide compound A 5.0 wt% chip, a polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C., and the mixing ratio of the polycarbodiimide compound A 5.0 wt% chip is 20 wt%. The mixture was mixed with a chip mixer so that the raw material of the spunbond nonwoven fabric was obtained. The obtained raw material was melted at 230 ° C., spun from the pores at a die temperature of 235 ° C., spun at a spinning speed of 4300 m / min by an ejector, and the web obtained by collecting on the moving net conveyor was collected. A spunbonded non-woven fabric with a single fiber fineness of 1.6 dtex and a basis weight of 100 g / m ² is produced by thermocompression bonding with an embossing roll and flat roll with a convex area of 16% at a temperature of 145 ° C. and a linear pressure of 60 kg / cm ^2. did. The terminal carboxyl group concentration of the obtained spunbonded nonwoven fabric was 7.0 equivalent / ton, and the strong elongation index reduction rate was 17.2%.

This biodegradable nonwoven fabric has a strong elongation index decrease rate of 17.2% and is a spunbond nonwoven fabric having a basis weight of 100 g / m ^2. Agricultural materials such as up-seats, electrical product packaging materials, handbags, futon storage bags and other household materials, filters and other industrial materials, ceiling materials, anti-noise materials and other automotive materials, roofing materials, roofing materials, sound absorbing materials, etc. It can be judged that it is optimal for the use of building materials.

Example 1
TIC was added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt-kneading to produce a chip having a TIC content of 5.0 wt%.

  To a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C., ethylene bis stearamide (hereinafter referred to as EBA, Alfro H-50T manufactured by NOF Corporation) was added by melt kneading, and EBA A chip having a content of 5.0 wt% was produced.

The prepared TIC 5.0 wt% chip, EBA 5.0 wt% chip, polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C., and the mixing ratio of TIC 5.0 wt% chip is 10 wt. %, EBA 5.0 wt% was mixed by a chip mixing device so that the mixing ratio of chips was 10 wt%, and used as a raw material for the spunbond nonwoven fabric. The obtained raw material was melted at 230 ° C., spun from the pores at a die temperature of 235 ° C., spun at a spinning speed of 4300 m / min by an ejector, and the web obtained by collecting on the moving net conveyor was Biodegradation according to the present invention with a single fiber fineness of 1.6 dtex and a basis weight of 30 g / m ² by thermocompression bonding under conditions of a temperature of 145 ° C. and a linear pressure of 25 kg / cm with an embossing roll and a flat roll having a convex area of 16% A spunbond nonwoven fabric was produced. The resulting spunbonded nonwoven fabric had a terminal carboxyl group concentration of 6.5 equivalents / ton and a strong elongation index reduction rate of 15.5%.

This biodegradable nonwoven fabric is a spunbond nonwoven fabric with a strong elongation index decrease rate of 15.5% and a basis weight of 30 g / m ^2. It could be judged to be optimal for uses such as household materials such as wood and cleaning covers, industrial materials such as filters, automotive materials such as ceiling materials, building materials such as roof coverings and decorative backing materials.

Comparative Example 4
TIC was added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt-kneading to produce a chip having a TIC content of 5.0 wt%. The prepared TIC 5.0 wt% chip and a polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. are mixed so that the mixing ratio of the TIC 5.0 wt% chip is 20%. It was mixed with an apparatus to obtain a raw material for the spunbonded nonwoven fabric. The obtained raw material is a sheath component, a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. is used as a core component raw material, and both the core component and the sheath component are melted at 230 ° C. After spinning as a core-sheath composite fiber with a sheath component ratio of 20 vol% from the pores at 235 ° C., the web spun by the ejector at a spinning speed of 4300 m / min and collected on the moving net conveyor A spunbonded nonwoven fabric having a single fiber fineness of 1.6 dtex and a basis weight of 50 g / m ² was manufactured by thermocompression bonding with an embossing roll having a surface area of 16% and a temperature of 145 ° C. and a linear pressure of 25 kg / cm. The terminal carboxyl group concentration of the obtained spunbonded nonwoven fabric was 17.6 equivalent / ton, and the strong elongation index reduction rate was 25.5%.

Since this biodegradable nonwoven fabric is a spunbond nonwoven fabric having a strength elongation reduction rate of 25.5% and a basis weight of 50 g / m ² , it can be used for agricultural materials such as seedling pots, sugar up sheets, and packaging of electrical products. Applications such as bags, wrapping materials, household materials such as simple clothing, industrial materials such as filters, automotive materials such as ceiling materials, airbag wrapping materials, trunk room interior materials, building materials such as roofing materials, roofing materials, and sound insulation materials It was possible to judge that it was optimal.

Reference example 1
TIC was added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt-kneading to produce a chip having a TIC content of 5.0 wt%. The prepared TIC 5.0 wt% chip and a polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. are mixed so that the mixing ratio of the TIC 5.0 wt% chip is 10%. It mixed with the apparatus and it was set as the raw material of the short fiber nonwoven fabric. The obtained raw material was melted at 230 ° C., spun from the pores at a die temperature of 240 ° C., and then undrawn yarn was wound up at a speed of 1600 m / min. Subsequently, the obtained undrawn yarn was drawn using a hot roll-hot roll type drawing machine at a drawing temperature of 80 ° C. and a heat setting temperature of 116 ° C., setting the draw ratio to 40%, and drawing the fineness. Of 2.2 dtex was obtained. Subsequently, the drawn yarn and the undrawn yarn were crimped using a crimper, cut to a fiber length of 6 mm, undrawn short fibers having a crimp number of 13.2 threads / 2.54 cm, and a crimp number of 13.5 threads. /2.54 cm stretched short fiber was obtained. By using a high-pressure homogenizer for the obtained short fibers of the drawn yarn, the fiber suspension is passed through a small-diameter orifice at a high speed, and then is rapidly decelerated by colliding with a wall near the orifice outlet. A cutting action was given to fibrillated short fibers.

The obtained drawn short fibers, undrawn short fibers and fibrillated short fibers are mixed and dispersed in a water tank at a blending ratio of 60:15:25, and then the mixed solution of fibers and water is used with a mesh drum. Then, while rotating this drum, the fiber and water were separated, and the wet nonwoven fabric was rolled up. This is squeezed using two rolls, then dried on the surface of a drum dryer having a surface temperature of 110 ° C., and further hot pressed at a linear pressure of 300 kg / cm using a calendar roll having a surface temperature of 140 ° C. The undrawn yarn was then fused to produce a wet nonwoven fabric with a single fiber fineness of 2.4 dtex and a basis weight of 80 g / m ² . The resulting wet nonwoven fabric had a terminal carboxyl group concentration of 7.1 equivalent / ton, and a strong elongation index reduction rate of 19.5%.

Since this biodegradable nonwoven fabric is a wet nonwoven fabric having a strong elongation index decrease rate of 19.5% and a basis weight of 80 g / m ² , agricultural materials such as nursery pots, wrapping materials, electrical product packaging materials, etc. It can be judged that it is most suitable for uses such as industrial materials such as daily life materials, filters, wire clamps, battery separators, automobile materials such as spare tire cover materials, and building materials such as soundproofing materials.

Reference example 2
TIC was added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt-kneading to produce a chip having a TIC content of 5.0 wt%. The prepared TIC 5.0 wt% chip and a polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. are mixed so that the mixing ratio of the TIC 5.0 wt% chip is 20%. It mixed with the apparatus and it was set as the raw material of the short fiber nonwoven fabric. The obtained raw material was an island component, copolymer polystyrene was a sea component, and melt spinning was performed at an island / sea weight ratio of 30/70 through a sea-island die having a number of islands of 70 / hole to obtain an undrawn yarn. The obtained undrawn yarn was drawn at a draw ratio of 3.0 times, cut with crimps, and a sea-island composite fiber raw cotton having a fiber length of 51 mm was obtained. The obtained raw material of sea-island type composite fiber was passed through a card and cross wrapping process to obtain a laminated web, and then a needle punch of 100 / cm ² was performed with a pre-punch to obtain a short fiber nonwoven fabric.

Subsequently, from the upper and lower sides of the obtained short fiber nonwoven fabric sheet, needle punching is performed with the number of needles of 1500 / cm ² , and then the fiber is made into ultrafine fibers, whereby a short fiber nonwoven fabric having a single fiber fineness of 0.02 dtex and a basis weight of 250 g / m ^2. Manufactured. The resulting short fiber nonwoven fabric had a terminal carboxyl group concentration of 5.0 equivalents / ton and a strong elongation index reduction rate of 11.4%.

This biodegradable nonwoven fabric has a strong elongation index decrease rate of 11.4% and is a short fiber nonwoven fabric with a basis weight of 250 g / m ^2. Ideal for materials, handbags, household materials such as electrical packaging materials, industrial materials such as filters and industrial wipers, automotive materials such as ceiling materials and anti-noise materials, building materials such as sound absorbing materials and heat insulating materials It was something that could be judged.

The properties of the nonwoven fabrics obtained in Example 1, Comparative Examples 1 to 4, and Reference Examples 1 and 2 are as shown in Table 1 . All of these nonwoven fabrics had a high elongation index decrease rate of less than 30.0%, and were excellent in hydrolysis resistance. Moreover, these nonwoven fabrics had a favorable production environment with no generation of irritating odors when produced. Especially, the thing of Example 1 of this invention is the most excellent in hydrolysis resistance in the spunbonded nonwoven fabric with the strong elongation index decreasing rate being as small as 15.5%.

Comparative Example 5
A polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. is used as a raw material, melted at 230 ° C., spun from the pores at a die temperature of 235 ° C., and then spun at a spinning speed of 4300 m by an ejector. The web obtained by spinning on a moving net conveyor is thermocompression bonded with an embossing roll and a flat roll with a convex area of 16% at a temperature of 145 ° C. and a linear pressure of 25 kg / cm. A spunbonded nonwoven fabric having a single fiber fineness of 1.6 dtex and a basis weight of 30 g / m ² was produced. The terminal carboxyl group concentration of the obtained spunbonded nonwoven fabric was 22.8 equivalent / ton, and the strong elongation index reduction rate was 55.8%.

Since this biodegradable nonwoven fabric is a spunbond nonwoven fabric with a basis weight of 30 g / m ² , it has been studied as a use for household materials such as electrical product packaging materials and automobile materials such as ceiling materials. Was 55.8%, and from this point, it could be judged unsuitable for the same application.

Comparative Example 6
2,2′-m-phenylenebis (2-oxazoline) (hereinafter referred to as PBO) is added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt-kneading. A raw material chip having a content of 0.5 wt% was produced. The obtained raw material was melted at 230 ° C., spun from the pores at a base temperature of 235 ° C., spun at a spinning speed of 4000 m / min by an ejector, and the web collected on the moving net conveyor was A spunbonded nonwoven fabric having a single fiber fineness of 1.8 dtex and a basis weight of 50 g / m ² was produced by thermocompression bonding with an embossing roll and a flat roll having a part area of 16% under the conditions of a temperature of 145 ° C. and a linear pressure of 25 kg / cm. The resulting spunbonded nonwoven fabric had a terminal carboxyl group concentration of 21.2 equivalent / ton and a strong elongation index reduction rate of 53.4%.

Since this biodegradable nonwoven fabric is a spunbond nonwoven fabric with a weight per unit area of 50 g / m ² , automobiles such as daily life materials such as electrical product packaging materials, industrial materials such as filters, ceiling materials, airbag wrapping materials, trunk room interior materials, etc. Although it was examined as a use of building materials such as materials and roofing materials, the strength index decrease rate was 53.4%, and from this point, it could be judged unsuitable for the same use.

The properties of the obtained nonwoven fabric are as shown in Table 1, but the nonwoven fabric of Comparative Example 5 had a strength index decrease rate of 30.0% or more and was inferior in hydrolysis resistance. Further, the nonwoven fabric of Comparative Example 6 had little terminal carboxyl group blocking effect, had a strong elongation index decrease rate of 30.0% or more, and was inferior in hydrolysis resistance.

  The biodegradable nonwoven fabric of the present invention has a favorable production environment without generation of irritating odors when produced, and a biodegradable nonwoven fabric excellent in hydrolysis resistance can be obtained. Civil engineering materials, agricultural materials such as bedding sheets, nursery pots, household materials such as handbags and wrapping materials, industrial materials such as filters and wire clamps, vehicle materials such as ceiling materials and floor mats, It can be applied to building materials such as moisture permeable waterproof sheets and roofing materials.

Claims (5)

A biodegradable non-woven fabric containing fibers made from an aliphatic polyester resin having a carboxyl group at the molecular chain terminal, and a terminal carboxyl of the aliphatic polyester resin by a monocarbodiimide compound having a 5% weight loss temperature of 170 ° C or higher. A part or all of the groups are blocked, and the rate of decrease in the strength elongation index under a wet heat atmosphere is less than 30% , and an aliphatic bisamide and / or an alkyl-substituted aliphatic monoamide is 0.1 to 5 A biodegradable spunbonded nonwoven fabric containing 0.0 wt% . A biodegradable nonwoven fabric containing a core-sheath composite fiber made of an aliphatic polyester resin having a carboxyl group at the molecular chain end, wherein only the sheath component resin of the core-sheath composite fiber has a 5% weight loss temperature of 170 ° C or higher. Part or all of the terminal carboxyl groups are blocked by the monocarbodiimide compound, and the sheath component ratio of the core-sheath composite fiber is 5 to 70 vol%, and the rate of decrease in the strength elongation index in a wet heat atmosphere is 30%. And a biodegradable spunbonded nonwoven fabric containing 0.1 to 5.0 wt% of an aliphatic bisamide and / or an alkyl-substituted aliphatic monoamide . The biodegradable spunbonded nonwoven fabric according to claim 1 or 2 , wherein the terminal carboxyl group concentration is 0 to 20 equivalent / ton. The biodegradable spunbonded nonwoven fabric according to any one of claims 1 to 3 , wherein the aliphatic polyester resin is a polylactic acid resin. A material comprising the biodegradable spunbonded nonwoven fabric according to any one of claims 1 to 4 .